Typical conventional locking devices, such as padlocks and luggage locks, require user to manually enter a sequence of numbers by adjusting multi-rotating dials inscribed with numeric digits to open a lock. This type of locking devices is commonly known as Combination Locks and they usually do not require a mechanical key. Instead users need to preset a combination digit code and remember this code when unlocking such locks. In contrast, existing electronic locks are usually designed with a bulky and relatively large numeric keypad for entering access codes. These keypads are not suitable for used in small size electronic combination locks.
The invention is concerned with small size electronic combination locks. In particular, the invention relates to miniaturization and an easy-to-use electronic identification method for setting locking and unlocking combination access code of electronic combination locks such as padlocks, chain locks, luggage locks, wire locks and bicycle locks.
The method of adjusting mechanical combination codes to unlock conventional locking devices is cumbersome and time consuming. The problems of using such combination locks are as follows: (1) reading and adjusting small size of inscribed digits on the rotating dials become tedious and time consuming (2) limited numeric digits from 0 to 9 resulted little choices of access code that can be formed by user (3) memorizing multiple numeric digits of access codes can be difficult to some users.
In addition to above shortcomings of conventional combination locks, there has been a need for a small electronic lock operated by an electronic identification device with characteristics as follows: easy to use due to its simplicity, increased variety of choices of combination codes, very low battery power consumption, and relatively inexpensive construction.
U.S. Pat. No. 4,495,540, describes an electronic combination lock for luggage. The electronic combination lock described in this patent comprises several buttons which emulate the mechanical adjustable rings in conventional combination locks. It is a replicate of multi-digit mechanical adjustable rings to several electronic push buttons. These multiple buttons method of entering access code is not suitable for application in small electronic combination locks. The patent is incorporated here for reference.
The followings additional patents are believed to have relevance to the invention: U.S. Pat. No. 3,754,164, U.S. Pat. No. 4,931,789, U.S. Pat. No. 5,021,776, U.S. Pat. No. 5,153,561, U.S. Pat. No. 5,373,718,
To address the weaknesses and the needs described above, the inventor proposed an alternative electronic combination lock which provides the public with a useful choice.